The use of a local anesthetic is essential for rendering medical care in a great multitude of situations. Probably, the most common is the injection of a local anesthetic in or about the teeth or jaw to carry on conventional, routine or extended dental work. Another example is pediatric dental work for reasons peculiar to young children. The practice of veterinary medicine requires the use of a local anesthetic often. Several examples of problems directly relating to the local anesthetic should be noted. While the problems may seem in past circumstances to be a mere inconvenience to adults, problems nevertheless can be compounded for the reasons described.
In pediatric dentistry, there is a risk of postoperative child or infant trauma as a result of the numbness in and about the mouth. It is possible for a very young child to unintentionally chew on their tongue, lip, cheek, etc. where the feeling is slow to recover. Significant injuries can potentially occur in these circumstances. In adults who have been treated for dental work, several hours may pass before the discomfort of the local anesthetic has worn off. Until that occurs, many adults speak with a thickened tongue, perhaps have discomfort during eating, and are otherwise inconvenienced.
Many medical procedures are undertaken with the assistance of a local anesthetic such as localized minor surgery or surgery on the limbs or other extremities. The numbness may last several hours. If the minor surgery under local anesthetic involves hands or feet, a person may have difficulty in using their limbs because they do not have the required tactile response or they may otherwise walk in a very wooden fashion. If a larger area is treated, it may require several hours for the numbness to wear off so that bodily sensation is restored.
A greater problem arises in veterinary surgery. There is a tendency for animals treated with a local anesthetic to chew in the region of the surgical work, perhaps mutilating the entire surgical site. As will be understood, it is not possible to orally caution very young children or animals for the interval necessary for the local anesthetic to wear off.
On a larger scale, there is the risk of excessive local anesthetic injection which has a cumulative toxicity in the entire body. It is common for Dentists to determine the approximate body weight of the patient, note the time of the first injection, calculate the rate at which the anesthetic is metabolized by the body and meter subsequent injections to avoid approaching threshold levels of toxicity. It is possible, but somewhat rare, for people to succumb to anesthetic toxicity, even to the point of death. In the event of prolonged dental or surgical work under local anesthetic, certain precautions must be undertaken. The present injectable and the method of administration contemplate reversal of the local anesthetic effect to avoid threshold toxicity conditions and thereby avoid systemic shock, perhaps toxic poisoning even to the extent of patient death.